Many implantable medical devices are coated with drugs that are eluted from the medical device upon implantation. For example, some vascular stents are coated with a drug which is eluted from the stent for treatment of the vessel and/or to prevent some of the unwanted effects and complications of implanting the stent. In such drug-eluting medical devices, various methods have been proposed to control the release and targeting of the eluted drug. However, because such methods have certain disadvantages, there is a need for an improved method of controlling the release and targeting of drugs eluted from medical devices.